import java.util.Date;

public class DateTimeTest1 {
    public static void main(String[] args) {
        //当前系统的时间
        Date date1 = new Date();
        System.out.println(date1);

        long millis = date1.getTime();
        System.out.println(millis);

        Date date2 = new Date(millis - 3600000);
        System.out.println(date2);
    }
}
